Electric switch



June 27, 1961 s, v, WORTH ET AL 2,990,460

ELECTRIC SWITCH Filed Sept. 3, 1959 INVENTORS SIDNEY V. WORTH ROBERT C.REBLING ZLzaV/y-M ATTORNEY Ice Patented June 27, 1961 2,990,460 ELECTRICSWITCH Sidney V. Worth, Philadelphia, and Robert C- Rebling, Abington,Pa., assignors to Electro Controls, Inc., a corporation of PennsylvaniaFiled Sept. 3, 1959, Ser. No. 837,827 11 Claims. (Cl. 200-33) Thepresent invention relates to an electric switch, and more particularlyto an electric switch having a time delay between the actuation of theswitch to its on position and the actual closing of the switch.

For the operation of many types of electrically operated devices, it isoften desirable to have a switch which will provide a delay time betweenthe actuation of the switch to its on position, and the actual closingof the switch, but which will provide substantially no delay timebetween the actuation of the switch to its oil position and the openingof the switch. Furthermore, it is also desirable to have such a switchin which the delay time between the actuation of the switch to its onposition and the actual closing of the switch can be varied.

It is an object of the present invention to provide a novel electricswitch.

It is another object of the present invention to provide a novelelectric switch having a delay period between the actuation of theswitch to its on position and the actual closing of the switch.

It is still another object of the present invention to provide anelectric switch having a delay period between the actuation of theswitch to its on position and the actual closing of the switch, buthaving substantially no delay time between the actuation of the switchto its oif position and the opening of the switch.

It is a further object of the present invention to provide an electricswitch having a time delay between the actuation of the switch to its onposition and the actual closing of the switch, which delay time can bevaried.

Other objects will appear hereinafter.

For the purpose of illustrating the invention there is shown in thedrawings forms which are presently preferred; it being understood,however, that this invention is not limited to the precise arrangementsand instrumentalities shown.

FIGURE 1 is a side elevational view of the electric switch of thepresent invention in its off position.

FIGURE 2 is an end elevational view of the switch of the presentinvention in its ofi position.

FIGURE 3 is a top elevational view of the switch of the presentinvention in its ofi position.

FIGURE 4 is a sectional View taken along line 4--4 with the switch beingin its on position.

FIGURE 5 is a side elevational view of the switch of the presentinvention in its on position.

FIGURE 6 is a sectional view through a modification of the switch of thepresent invention.

FIGURE 7 is a view taken along line 7-7 of FIG- URE 6.

FIGURE 8 is a schematic View of still another modification of the switchof the present invention.

Referring initially to FIGURES 1-3, the switch of the present inventionis generally designated as 10.

Switch 10 comprises a vertical mounting plate 12 which is pivotallysupported intermediate its ends on a supporting bracket 14. Supportingbracket 14 comprises a horizontal base 16, and a pair of spaced,parallel legs 18 extending upright from the base 16. The mounting plate12 is pivotally supported between the legs 18 of the mounting bracket 14by a horizontal pivot pin 20 which extends through the legs 18 and themounting plate 12. Thus, the mounting plate 12 is supported forpivotation about a horizontal axis.

A pair of parallel tubes 22 and 24 extend through and are secured to themounting plate 12 adjacent opposite ends of the mounting plate 12. Thetubes 22 and 24 are of equal length, and project the same distancebeyond each side of the mounting plate 12. A tube 26 extends along oneside of the mounting plate 12, and connects one end of the tube 22' toone end of the tube 24. A tube 28 extends along the other side of themounting plate 12 and connects the other end of the tube 22 to the otherend of the tube 24. The tubes 22, 24, 26, and 28 are connected to form aclosed passageway extending through the tubes. The tubes 22 and 24 areangled downwardly in opposite directions with respect to each other.Thus, the corner 30 at the junction between the tube 22 and the tube 26is vertically higher than the corner 32 at the junction between the tube22 and the tube 28, whereas the corner 34 at the junction between thetube 24 and the tube 28 is higher than the corner 36 at the junctionbetween the tube 24 and the tube 26. The tubes 22, 24, 26, and 28 aremade of an electrical insulating material such as a plastic.

A pair of electrically conductive metal terminals 38 and 40 extendthrough the corner 36 at the junction between the tube 24 and the tube26. The terminal 38 extends downwardly through the top of the corner 36,and the terminal extends upwardly through the bottom of the corner 36.An electrically conductive liquid 42, such as mercury, is providedwithin the closed passageway provided by the tubes 22, 24, 26, and 28'.

A valve 44 is provided in the tube 28 between the corners 32 and 34.Valve 44 may be any well known type of valve having a variable sizeopening therethrough for controlling the flow through the valve 44.Valve 44 has a handle 46 by which the size of the opening through thevalve 44 can be varied. An actuating rod 48 is pivotally connected toone end of the mounting plate 12 by which the switch 10 can be actuatedbetween its off and on positions.

The switch 10 of the present invention operates as follows:

The switch 10 is in its oil position when the actuating rod 48 is pulleddownwardly so that the tube 22 is lower than the tube 24. In thisposition of the switch 10, the corner 32' is lower than the corners 30,34, and 36, so that all of the liquid 42 will be in the corner 32.

To actuate the switch 10 to its on position, and thereby close theswitch 10, the rod 48 is pushed upwardly to pivot the mounting plate 12until the tube 24 is lower than the tube 22 as shown in FIGURE 5. Inthis position of the switch 10, the corner 36 is lower than the corners30, 32, and 34 so that all of the liquid 42 will flow from the corner 32to the corner 36. Since the corner 30 is always higher than the corner32, the liquid 42 cannot flow from the corner 32 to the corner 36through the tube 22 and tube 26. Thus, all of the liquid 42 flows downthe tube 28 and down the tube 24 to the corner 36.

When the corner 36 becomes completely filled with the liquid 42 which iselectrically conductive, the terminals 38 and 40 will be electricallyconnected through the liquid 42 to close the switch 10. There is just asuflicient amount of the liquid 42 in the tubes so that all of theliquid 42 must be in the corner 36 before the corner 36 is completelyfilled to electrically connect the terminals 38 and 40. During thepassage of the liquid 42 from the corner 32 to the corner 36, the liquid42 must pass through the valve 44. The valve 44 restricts the flow ofthe liquid 42 so as to provide a time delay between the time that themounting plate 12 was pivoted to its on position and the time that allof the liquid 42 reaches the corner 36 to electrically connect theterminals 38 and 40 and thereby electrically close the switch 10. Theparticular delay time of the switch 10 is determined by the size of the3 opening through the valve 44 which can be varied by turning the handle46.

To open the switch 10, the actuating rod 48 is pulled downwardly againto pivot the mounting plate 12 to its off position in which the tube 22is lower than the tube 24 as shown in FIGURE 1. In the ofl": position ofthe switch 10, the corner 32 is lower than the corners 30, 34, and 36 sothat all of the liquid 42 will flow from the corner 36 to the corner 32.Since the corner 34 is always higher than the corner 36, the liquid 42cannot flow from the corner 36 back through the tube 24, but the liquid42 must flow through the tube 26 and the tube 22 to the corner 32. Assoon as some of the liquid 42 leaves the corner 36, the corner 36 willbe emptied sufliciently to electrically disconnect the terminals 38 and40, and thereby open the switch 10. Thus, although the switch provides atime delay between the actuation of the switch to its on position andthe electrically closing of the switch 10, there is substantially notime delay between the actuation of the switch 10 to its off positionand the electrically opening of the switch 10.

Referring to FIGURES 6 and 7, a modification of the switch of thepresent invention is generally designated as 10a. Switch 10a isidentical to the switch 10 shown in FIGURE 1, except with regard to themeans for restricting the flow of the liquid 42 to provide the timedelay.

In the switch 10a, the means for restricting the flow of the liquid 42comprises a tube 50' of a flexible plastic, which tube 50 is eitherinserted into or entirely replaces the tube 28 of the switch 10 ofFIGURE 1. A clamp 52 is provided around the flexible tube 50. Clamp 52comprises a pair of flat arms 54 which are pivotally connected togetherat one end by a pivot pin 56. The free ends 58 of the clamp arms 54 arebent through substantially 300 to encircle a separate pin 60. Each ofthe arms 54 has a slot 62 extending longitudinally therethrough from thefree end 58 of the arm 54. A screw 64 extends transversely through oneof the pins 60, across the space between the arms 54, and is threadedinto the other pin 60. The screw 64 extends through the slots 62 in thearms 54.

The switch 10a operates in the same manner as the switch 10 aspreviously described. To vary the time delay of the switch 1012, thescrew 64 is rotated to either pull the arms 54 of the clamp 52 together,or spread the arms 54 ot the clamp 52 apart. When the arms 54 of theclamp 52 are pulled together, the arms 54 squeeze the flexible tube 50therebetween, and close the passageway through the tube 50 to decreasethe delay time. When the arms 54 of the clamp 52 are spread apart, thepassage through the flexible tube 50 is opened to decrease the delaytime.

Although the switch 10 of the present invention is shown having only onepair of terminals 38 and 49, the

switch 10 can also be provided with an additional pair of the terminalsin the lower corner 32 between the tubes 22 and 28 and with a secondvalve in the tube 26. Thus there would be provided a double throw switchhaving a delay time for closing both sets of terminals. Since the liquid42 would have to pass through different valves to reach each of the setsof terminals, the delay time for each set of terminals can be difierent.Also, although the terminals 38 and 40 are shown extending respectivelythrough the top and bottom of the corner 36, both of the terminals 38and 40 can extend through either the top, or the bottom or the sides ofthe corner 36.

Referring to FIGURE 8, the modification of the switch .of the presentinvention is generally designated as 70.

Switch 70 comprises a single tube 72 of an electrical insulatingmaterial which is closed at both ends. One end of the tube 72 is securedto the end of a mounting plate 74. Mounting plate 74 is pivotallysupported on a supporting bracket 76. An actuating rod 78 is pivotallyconnected to the other end of the mounting plate 7 4.

A valve 80 is provided in the tube 72 between the ends of the tube 72.Valve may be any type of restriction means for reducing the area of thetube 72 and which permits the restricted area to be varied. A pair ofterminals 82 and 84 extend through the tube 72 adjacent the free end ofthe tube 72. The tube 72 contains an electrically conductive liquid 86,such as mercury.

In the use of the switch 70, the switch 70 is in its off position whenthe actuating rod 78 is pulled downwardly to lift the free end of thetube 72 up. The liquid 86 flows to the supported end of the tube 72 andthereby disconnects the terminals 82 and 84. When the actuating rod 78is pushed upwardly to lower the free end of the tube 72, the liquid 86flows through the valve 80 to the terminals 82 and 84. The valve 80restricts the flow of the liquid 86 so that there is a delay time beforea sulficient amount of the liquid 86 reaches the free end of the tube 72to electrically connect the terminals 82 and 84. The tube 72 may also beprovided with a pair of terminals adjacent its supported end to providea double throw switch.

As shown in FIGURE 8, the tube 72 of the switch 70 has a pair ofterminals 88 and 90 therethrough adjacent the valve 80. When the switch70 is actuated to the on position of the tube '72, the liquid 86 flowsthrough the valve 80 and across the terminals 88 and 90 to electricallyconnect the terminals 88 and 90. As long as the liquid 86 flows acrossthe terminals 88 and 90 the electrical circuit containing the terminals88 and 90 is closed. The length of time that the terminals 88 and 90will remain connected is determined by the restriction of the valve 80.Thus, if the valve 80 is wide open, the liquid 86 will flow quicklyacross the terminals 88 and 90 to connect the terminals 88 and 90 onlyfor a short period. However, if the valve 80 is closed to provide only asmall opening, the liquid will flow across the terminals 88 and 90 for alonger period.

Thus, by using the terminals 88 and 90 which are spaced from the ends ofthe tube 72, the switch 70 can be used to maintain a circuit closed fora desired period of time. The switch 70 of the present invention permitsthe time of maintaining the circuit closed to be varied as desired. Theswitch 10 of the present invention may also be provided with a pair ofterminals spaced from the lower corners 36 or 32 to permit the closingof a circuit for a desired length of time.

The present invention may be embodied in other specific forms withoutdeparting from the spirit or essential attributes thereof and,accordingly, reference should be made to the appended claims, ratherthan to the foregoing specification as indicating the scope of theinvention.

We claim:

1. A time delay switch comprising a mounting plate supported forpivotation about a horizontal axis, a pair of tubes extending throughand supported by said mounting plate, said tubes extending downwardly inopposite directions so that one pair of diagonally opposite ends of saidtubes are lower than the other pair of diagonally opposite ends, asecond pair of tubes, each of said second pair of tubes connecting ahigher end of one of said first pair of tubes to the lower end of theother of said first pair of tubes, said tubes being connected togetherto provide a closed passageway therethrough, a pair of electricalterminals extending through the low end of one of said first pair oftubes, an electrically conductive liquid within said tubes, and meansfor restricting the flow of the liquid from the low end of the other ofsaid first pair of tubes to the low end of said one of the first pair oftubes.

2. A switch in accordance with claim 1 in which the amount of theelectrically conductive liquid within said tubes is just suflicient tobridge the space between the terminals when all of the liquid is in thelow end of the one tube of the first pair.

3. A switch in accordance with claim 1 in which the means forrestricting the flow of the fluid comprises a valve having an openingtherethrough which is smaller in area than the area of said tubes.

4. A switch in accordance with claim 3 in which the valve has a variablesize opening therethrough.

5. A switch in accordance with claim 1 in which the means forrestricting the flow of the fluid comprises a flexible tube throughwhich the fluid must flow, and a clamp around said flexible tube andadapted to vary the size of the opening through said flexible tube.

6. A time delay switch comprising a mounting plate supported forpivotation about a horizontal axis, a hollow tube of electricalinsulating material, said tube being in the form of a quadrangle andbeing supported on said mounting plate with two of the sides thereofextending through the mounting plate and the other two sides thereofextending along oppositesides of said mounting plate, said quadrangulartube being twisted so that two of the diagonally opposite corners ofsaid tube are lower than the other two diagonally opposite corners, apair of electrical terminals extending through one of said lower cornersof said tube, an electrically conductive liquid within said tube, andmeans for restricting the flow of said liquid between the other lowercorner of said tube and said one lower corner which contains saidterminals.

7. A switch in accordance with claim 6 in which the amount of theelectrically conductive liquid within said tube is just suflicient tobridge the space between said terminals when all of the liquid is in theone lower corner of said tube.

8. A switch in accordance with claim 6 in which the means forrestricting the flow of the fluid comprises a valve having an openingtherethrough which is smaller in area than the area of said tube.

9. A switch in accordance with claim 8 in which the valve has a variablesize opening therethrough.

10. A switch in accordance with claim 9 in which said valve is mountedin the side of said tube which extends from said other lower corneralong the mounting plate.

11. A switch in accordance with claim 6 in which the means forrestricting the flow of the fluid comprises a flexible tube connected inthe tube between said other lower corner and the high corner on the sameside of the mounting plate, and a clamp extending around said flexibletube and adapted to vary the size of the opening of said flexible tube.

References Cited in the file of this patent UNITED STATES PATENTS1,998,254 Scott Apr. 16, 1935 2,615,100 Weaver Oct. 21, 1952 2,851,547Hertz Sept. 9, 1958

